A typical tiled shower stall floor comprises a shower pan formed over a sub-floor that includes an upper surface that slopes towards a shower drain. The pan is typically formed from a dry-set concrete material, but in some installations preformed and pre-sloped slabs of a suitable material may be used. A waterproofing is typically applied to the top surface of the pan extending several inches up the sides of the walls of the shower stall surrounding the pan. Often the form of the waterproofing comprises a waterproof membrane that is adhesively bonded to the pan.
All or part of one side of the stall usually includes an opening to allow egress and ingress to the stall. A curb approximately 3-6″ in height is often provided at the base of the opening to prevent water from flowing from the shower floor on to the rest of the floor of the associated bathroom. The membrane is also secured to at least the inside edge of the curb and often over the entire surface of the curb. A shower door may be installed above the curb to cover the opening.
The desired tile is installed over the membrane usually using traditional methods of applying mortar over the waterproofing and setting the tiles in place. Finally, as necessary the gaps between the tiles are grouted. In some installations, the tiles may further extend up the shower stall walls. Tiles are typically utilized to cover at least the inside and top surfaces of the curb if not the entire curb.
The laying and securing of the waterproof membrane to the substantially flat albeit sloped surface of the shower pan is straight forward as is extending the sheet on to and partially up a shower wall. More care and time is required in adjoining pieces of membrane where two walls meet, such as where the edge of a curb meets an adjacent wall. The edges of the membrane associated with each wall must be cut so as to overlap and one piece must be adhesively secured to the other. Further, membrane must be configured to extend over and around the intersection of the curb with adjoining walls. As can be appreciated significant amounts of installation time can be required to cut, fabricate and bond membrane in place that effectively water proofs the various underlying surfaces immediately surrounding and abutting the intersection.